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Physics of Radiography [email protected] www.sciencewow.co.uk Physics of Radiography • • • • • • • • • • Structure of an atom Wave theory Quantum theory of electromagnetic radiation Physical properties of X-rays X-ray spectra (continuous and emission line) X-ray tube Types of X-ray tube and power supplies Compton scattering Absorption process – matter & materials Dosimetry Physics of Radiography • Structure of an atom Properties of sub-atomic particles Structure of atom Energy levels Electron configuration Physics of Radiography • Wave theory Wave terminology Wave equation to calculate frequency and wavelength Physics of Radiography • Quantum theory of electromagnetic radiation Quantisation of energy The photon Wave particle duality Physics of Radiography • Physical properties of X-rays X-ray photon energies Frequency & wavelength of X-rays Physics of Radiography • X-ray spectra (continuous and emission line) Electronic transitions Line and continuous spectra Effect on spectra of varying accelerating voltage Maximum photon energy Physics of Radiography • X-ray tube Diagram of the x-ray tube Calculate electron kinetic energy (J) Convert J to eV Physics of Radiography • Types of X-ray tube and power supplies Power supply for electron tube High anode-cathode voltage Effect of high cathode current Physics of Radiography • Compton scattering Simple scattering Compton scattering Photoelectric effect Pair production Physics of Radiography • Absorption process – matter & materials Material thickness Different materials Attenuation Photographic image Image quality Image intensifiers Physics of Radiography • Dosimetry Absorbed dose, dose equivalent, effective dose Units ALARA principle